The known apparatus with rods, chains in oblong openings, and mounted on house entrance doors, do not satisfy all the conditions of the following problem.
A small child opens all the doors in a home which can be unpleasant for parents who must constantly watch over the child to avoid an accident.
The conditions to be fulfilled are the following:
(a) that the apparatus engage automatically upon door closing, avoiding forgetfulness; PA1 (b) that the apparatus be adaptable to swinging doors as well as sliding doors; PA1 (c) that the release of the closure latch, for opening, be very difficult or impossible for a small child; and PA1 (d) that in the case of a communicating door (stairway, cellar, workshop . . . ) the release be possible from both sides of the door.
Typical prior art latch assemblies are disclosed in U.S. Pat. No. 3,618,995 to McLean, granted Nov. 9, 1971; U.S. Pat. No. 3,782,765 to Wallyn, granted Jan. 1, 1974; U.S. Pat. No. 3,397,001 to Friedman, granted Aug. 13, 1968; and U.S. Pat. No. 3,889,992 to Shelton, granted June 17, 1975. Each of the aforesaid latch assemblies did not fully satisfy all of the aforesaid requirements.
Now there is provided by the apparatus in accordance with this invention, a latch assembly which satisfies these aforesaid conditions by the mounting of two parts which engage one within the other, one being affixed to the door frame and the other to the door leaf. To insure that the automatic engagement and voluntary release be possible, one of the two parts must be deflectable while the other remains rigid, in different mounting arrangements of the parts.